It doesn't typically get REALLY cold here, but sometimes it does and I have tossed around the question of a winter coat. I have been layering with sweaters and a really thick, really big hoodie (my mom bought it for my brother and he didn't like the color- its a man size 2x). It doesn't look that great with my work clothes, but I only wear it to and from work and don't have to work outside.
I saw the motherhood maternity coats on sale and almost bought one, but they didn't seem any warmer than my current hoodie set up, so I skipped it. However, in October I did travel for work to someplace that has pretty cold weather and a co-worker lent me her coat. She is not pregnant but plus sized (as am I, but she is probably 2 or 3 sizes bigger than me). Her coat was a nice wool coat that is in an a shape- and I am sure it would fit right up to the very end. If it gets really cold she said I could borrow it again and she would wear a different one. But looking at plus sized clearance (or a thrift store) might yield a better bargain for those who need to have their own winter coat.